Temp variations with H4831SC

[stomp442]

Been having some issues with H4831SC out of my .260 Ackley. The weather has been weird here the last couple weeks and will be in the low 60's one Saturday and mid 70's low 80's the next. The problem I'm having is when the temp warms up my point of impact changes by about 4" on the low side which is the opposite of everything I have experienced when temperature is concerned. The weather here in AZ can be quite drastic as far as temperature swings go and the main reason I wanted to use a powder that wasn't supposed to be so temperature sensitive. When shooting in the cooler weather my come up numbers are right on and when warm I have to add a minute to each number out to 400 meters and 1.5 minutes at 500 meters. Any one experiencing this type of problem with this powder? Am I asking to much of a powder to be able to handle 20 degree temp changes?

My particular barrel seems to prefer velocities on the low side which I am ok with since it shoots so good.
42 grains H4831SC
Lake City Match Brass
140gr Berger VLD
2740 fps
S.D. of 3 (wow)
and groups consistently under 2" at 500 meters.

[GaCop]

I never tried that powder in my 260. You may want to give a look at 8208XBR.

[kelbro]

I use that here in AZ for the 270 and do not see that much variance in our huge temp ranges.

Just developed some 243AI loads with it so I will not know until July :) how much it moves.

[darkker]

Unfortunatly, being on the "light side" of loads can cause as much "issue" as being on the heavy side...

H4831 has had some nasty variations for me as well. MOST of Hodgy's stick powders have given me fits at one time or another. H414/Win 760, and Win 748 have been by FAR the most stable for temp/pressure swings. You and I have about the same weather. 25 in the A.M. and 70-80 in the days.

[stomp442]

Yeah I'm going back to the drawing board to try and find another load on the higher end of the scale and see what that does. Got some loaded up with some varget ramshot hunter and H4350 and see how they do. During my initial load development everything I tried shot 1"-1.5" groups at 200 yards but the 42 grains of 4831SC just shot so good I stopped there not worrying about velocity as much as accuracy.

[stomp442]

Just as an update I spent friday afternoon and most of this morning working up loads with Varget, IMR 4064, H4350 and Ramshot Hunter. Best I could do with any of these was 1" groups at 200, fine for a hunting rifle but not what I am looking for. I did however find a higher end load of H4831SC at 44 grains with a velocity of 2940 able to group 5 shots under a quarter. Hopefully a little higher end load will fix the temp variations because my gun really really likes the H4831SC. I really wanted to try some reloader 17 but couldnt find any in town.

[darkker]

1", 5-shot groups @ 200 yards = 1/2 MOA groups.

"Fine for a hunting rifle" .... Unless you ONLY want heart shots, on gophers; that is SUPREME accuracy for a hunting rifle.

Hope you find whatever it is you are looking for.

[stomp442]

This is abench rifle though and should be capable of tighter groups.